/*
 * > /*
 >  * INSANE - Interactive Structural Analysis Environment
 >  *
 >  * Copyright (C) 2003-2004
 >  * Universidade Federal de Minas Gerais
 >  * Escola de Engenharia
 >  * Departamento de Engenharia de Estruturas
 >  *
 >  * Author's email :     insane@dees.ufmg.br
 >  * Author's Website :   http://www.dees.ufmg.br/insane
 >  *
 >  * This program is free software; you can redistribute it and/or
 >  * modify it under the terms of the GNU General Public License
 >  * as published by the Free Software Foundation; either version 2
 >  * of the License, or any later version.
 >  *
 >  * This program is distributed in the hope that it will be useful,
 >  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 >  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 >  * GNU General Public License for more details.
 >  *
 >  * You should have received a copy of the GNU General Public License
 >  * along with this program; if not, write to the Free Software
 >  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-
 > 1307, USA.
 *
 */

package br.ufmg.dees.insane.commons.view;

import java.io.File;
import java.util.Enumeration;
import java.util.Hashtable;

import javax.swing.filechooser.FileFilter;

/**
 * A convenience implementation of FileFilter that filters out all files except
 * for those type extensions that it knows about. This is based on
 * ExampleFileFilter of Sun Microsystems The Java Tutorial (see&nbsp; <a
 * HREF="http://java.sun.com/docs/books/tutorial/uiswing/components/filechooser.html">
 * http://java.sun.com/docs/books/tutorial/uiswing/components/filechooser.html
 * </a>). <br>Extensions are of the type ".foo", which is typically found on
 * Windows and Unix boxes, but not on Macinthosh. Case is ignored. <br><br>
 * Example - create a new filter that filerts out all files but gif and jpg
 * image files: <br>
 * 
 * <pre>
 * 
 *  
 *     JFileChooser chooser = new JFileChooser();
 *     ExampleFileFilter filter = new ExampleFileFilter(
 *                   new String{&quot;gif&quot;, &quot;jpg&quot;}, &quot;JPEG &amp; GIF Images&quot;)
 *     chooser.addChoosableFileFilter(filter);
 *     chooser.showOpenDialog(this);
 *  
 *  
 * </pre>
 * 
 * @author Fonseca, Flavio & Pitangueira, Roque
 */
public class ExtensionFileFilter extends FileFilter {

//    private static String TYPE_UNKNOWN = "Type Unknown";

//    private static String HIDDEN_FILE = "Hidden File";

    private Hashtable<Object, Object> filters = null;

    private String description = null;

    private String fullDescription = null;

    private boolean useExtensionsInDescription = true;

    // *****************************************************************************

    /**
     * Creates a file filter. If no filters are added, then all files are
     * accepted.
     * 
     * @see #addExtension
     */
    public ExtensionFileFilter() {
        this.filters = new Hashtable<Object, Object>();
    }

    // *****************************************************************************

    /**
     * Creates a file filter that accepts files with the given extension.
     * Example: <br>
     * 
     * <pre>
     * new ExampleFileFilter(&quot;jpg&quot;);
     * </pre>
     * 
     * @see #addExtension
     * @param extension
     *            The desired extension String.
     */
    public ExtensionFileFilter(String extension) {
        this(extension, null);
    }

    // *****************************************************************************

    /**
     * Creates a file filter that accepts the given file type. Example: <br>
     * 
     * <pre>
     * new ExampleFileFilter(&quot;jpg&quot;, &quot;JPEG Image Images&quot;);
     * </pre>
     * 
     * Note that the "." before the extension is not needed. If provided, it
     * will be ignored.
     * 
     * @see #addExtension
     * @param extension
     *            The desired extension String.
     * @param description
     *            The String describing the file type.
     */
    public ExtensionFileFilter(String extension, String description) {
        this();
        if (extension != null)
            addExtension(extension);
        if (description != null)
            setDescription(description);
    }

    // *****************************************************************************

    /**
     * Creates a file filter from the given string array. Example: <br>
     * 
     * <pre>
     * 
     *  
     *   new ExampleFileFilter(String {&quot;gif&quot;, &quot;jpg&quot;});
     *   
     *  
     * </Pre>
     * 
     * 
     *  Note that the &quot;.&quot; before the extension is not needed adn
     *  will be ignored.
     * 
     *  @see #addExtension
     *  @param filters  An array of String extensions.
     */
    public ExtensionFileFilter(String[] filters) {
        this(filters, null);
    }

    // *****************************************************************************

    /**
     * Creates a file filter from the given string array and description.
     * Example: <br>
     * 
     * <pre>
     * 
     *  
     *   new ExampleFileFilter(String {&quot;gif&quot;, &quot;jpg&quot;}, &quot;Gif and JPG Images&quot;);
     *   
     *  
     * </pre>
     * 
     * Note that the "." before the extension is not needed and will be ignored.
     * 
     * @see #addExtension
     * @param filters
     *            An array of String extensions.
     * @param description
     *            The String describing the filter.
     */
    public ExtensionFileFilter(String[] filters, String description) {
        this();
        for (int i = 0; i < filters.length; i++) {
            // add filters one by one
            addExtension(filters[i]);
        }
        if (description != null)
            setDescription(description);
    }

    // *****************************************************************************

    /**
     * Returns true if this file should be shown in the directory pane, false if
     * it shouldn't. Files that begin with "." are ignored.
     * 
     * @see #getExtension
     * @param f
     *            A file.
     * @see java.io.File
     * @return A boolean if accepted or not.
     */
    public boolean accept(File f) {
        if (f != null) {
            if (f.isDirectory()) {
                return true;
            }
            String extension = getExtension(f);
            if (extension != null && filters.get(getExtension(f)) != null) {
                return true;
            }
            ;
        }
        return false;
    }

    // *****************************************************************************

    /**
     * Returns the extension portion of the file's name .
     * 
     * @see #getExtension
     * @see FileFilter#accept
     * @param f
     *            A file.
     * @see java.io.File
     * @return The String extension.
     */
    public String getExtension(File f) {
        if (f != null) {
            String filename = f.getName();
            int i = filename.lastIndexOf('.');
            if (i > 0 && i < filename.length() - 1) {
                return filename.substring(i + 1).toLowerCase();
            }
            ;
        }
        return null;
    }

    // *****************************************************************************

    /**
     * Adds a filetype "dot" extension to filter against. For example: the
     * following code will create a filter that filters out all files except
     * those that end in ".jpg" and ".tif": <br>
     * 
     * <pre>
     * ExampleFileFilter filter = new ExampleFileFilter();
     * filter.addExtension(&quot;jpg&quot;);
     * filter.addExtension(&quot;tif&quot;);
     * </pre>
     * 
     * Note that the "." before the extension is not needed and will be ignored.
     * 
     * @param extension
     *            An String of the desired extension.
     */
    public void addExtension(String extension) {
        if (filters == null) {
            filters = new Hashtable<Object, Object>(5);
        }
        filters.put(extension.toLowerCase(), this);
        fullDescription = null;
    }

    // *****************************************************************************

    /**
     * Returns the human readable description of this filter. For example: "JPEG
     * and GIF Image Files (*.jpg, *.gif)"
     * 
     * @see #setDescription
     * @see #setExtensionListInDescription
     * @see #isExtensionListInDescription
     * @see FileFilter#getDescription
     * @return The String description of the filter.
     */
    public String getDescription() {
        if (fullDescription == null) {
            if (description == null || isExtensionListInDescription()) {
                fullDescription = description == null ? "(" : description
                        + " (";
                // build the description from the extension list
                Enumeration extensions = filters.keys();
                if (extensions != null) {
                    fullDescription += "." + (String) extensions.nextElement();
                    while (extensions.hasMoreElements()) {
                        fullDescription += ", "
                                + (String) extensions.nextElement();
                    }
                }
                fullDescription += ")";
            }
            else {
                fullDescription = description;
            }
        }
        return fullDescription;
    }

    // *****************************************************************************

    /**
     * Sets the human readable description of this filter. For example: <br>
     * 
     * <pre>
     * filter.setDescription(&quot;Gif and JPG Images&quot;);
     * </pre>
     * 
     * @see #setDescription
     * @see #setExtensionListInDescription
     * @see #isExtensionListInDescription
     * @param description
     *            The desired String description of the filter.
     */
    public void setDescription(String description) {
        this.description = description;
        fullDescription = null;
    }

    // *****************************************************************************

    /**
     * Determines whether the extension list (.jpg, .gif, etc) should show up in
     * the human readable description. Only relevent if a description was
     * provided in the constructor or using setDescription();
     * 
     * @see #getDescription
     * @see #setDescription
     * @see #isExtensionListInDescription
     * @param b
     *            A boolean to be set.
     */
    public void setExtensionListInDescription(boolean b) {
        useExtensionsInDescription = b;
        fullDescription = null;
    }

    // *****************************************************************************

    /**
     * Returns whether the extension list (.jpg, .gif, etc) should show up in
     * the human readable description. Only relevent if a description was
     * provided in the constructor or using setDescription();
     * 
     * @see #getDescription
     * @see #setDescription
     * @see #setExtensionListInDescription
     * @return A boolean if it is to show or not the extensions.
     */
    public boolean isExtensionListInDescription() {
        return useExtensionsInDescription;
    }

    // *****************************************************************************

}